U.S. patent application number 13/284071 was filed with the patent office on 2012-05-03 for electrochemical sensor, lancet, and bodily fluid measuring apparatus.
This patent application is currently assigned to ARKRAY, INC.. Invention is credited to Yoshimitsu Matsuura, Yoshiharu Sato, Shinichi Watanabe, Tadao Yamaguchi.
Application Number | 20120109010 13/284071 |
Document ID | / |
Family ID | 44905579 |
Filed Date | 2012-05-03 |
United States Patent
Application |
20120109010 |
Kind Code |
A1 |
Sato; Yoshiharu ; et
al. |
May 3, 2012 |
ELECTROCHEMICAL SENSOR, LANCET, AND BODILY FLUID MEASURING
APPARATUS
Abstract
An electrochemical sensor includes a base plate provided with a
concave part formed on one of surfaces thereof, a fluid channel
formed so that a bottom part of the concave part and the other one
of the surfaces of the base plate are communicated with each other,
a plurality of electrodes formed on the concave part; a reagent
fixed on the electrodes, a cover which covers the concave part, and
an air channel which causes the inside and outside of the concave
part to be communicated with each other.
Inventors: |
Sato; Yoshiharu; (Kyoto-shi,
JP) ; Yamaguchi; Tadao; (Kyoto-shi, JP) ;
Watanabe; Shinichi; (Kyoto-shi, JP) ; Matsuura;
Yoshimitsu; (Kyoto-shi, JP) |
Assignee: |
ARKRAY, INC.
Kyoto
JP
|
Family ID: |
44905579 |
Appl. No.: |
13/284071 |
Filed: |
October 28, 2011 |
Current U.S.
Class: |
600/583 ;
204/400 |
Current CPC
Class: |
G01N 27/3271 20130101;
A61B 5/150503 20130101; A61B 5/14532 20130101; A61B 5/150412
20130101; A61B 5/15115 20130101; A61B 5/150358 20130101; A61B 5/157
20130101; G01N 27/3272 20130101; A61B 5/1468 20130101; A61B 5/15194
20130101; A61B 2562/0295 20130101; A61B 5/1486 20130101; A61B
5/15107 20130101; A61B 5/150022 20130101; A61B 5/1411 20130101 |
Class at
Publication: |
600/583 ;
204/400 |
International
Class: |
A61B 5/00 20060101
A61B005/00; G01N 27/26 20060101 G01N027/26 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 29, 2010 |
JP |
2010-243163 |
Claims
1. An electrochemical sensor, comprising: a base plate provided
with a concave part formed on one of surfaces thereof; a fluid
channel formed so that a bottom part of the concave part and the
other one of the surfaces of the base plate are communicated with
each other; a plurality of electrodes formed on the concave part; a
reagent fixed on the electrodes; a cover which covers the concave
part; and an air channel which causes the inside and outside of the
concave part to be communicated with each other.
2. The electrochemical sensor according to claim 1, wherein an
outer edge shape in planar view is a triangle, a trapezoid, or a
circle.
3. The electrochemical sensor according to claim 1, wherein the
fluid channel is a through-hole formed at the center of the concave
part in planar view, and formed in a direction that is orthogonal
to the base plate.
4. The electrochemical sensor according to claim 1, wherein the air
channel includes at least one air hole formed in the cover.
5. The electrochemical sensor according to claim 4, wherein a
planar view shape of the concave part is formed in a triangle, and
the air channel includes three air holes formed respectively at
positions corresponding to apex portions of the triangle of the
cover.
6. The electrochemical sensor according to claim 4, wherein a
planar view shape of the concave part is formed in a circle, and
the air channel includes an air hole formed on the cover and
disposed so as to overlap with the through-hole in a planar view
state of the base plate.
7. The electrochemical sensor according to claim 1, further
comprising: a pair of second concave parts formed around the
concave part, wherein the plurality of electrodes include: a first
electrode pattern in which an electrode extending from the concave
part to one of the pair of second concave parts and an electrode
removal part are formed integrally; and a second electrode pattern
which is insulated from the first electrode pattern, and in which
an electrode extending from the concave part to the other one of
the pair of second concave parts and an electrode removal part are
formed integrally.
8. The electrochemical sensor according to claim 1, wherein the
other one of the surfaces of the base plate is recessed inward.
9. A lancet, comprising: a lancet body; a mounting part which is
provided to the lancet body and to which an electrochemical sensor
having one surface and the other surface is mounted in a state of
the one surface facing the lancet body and the other surface facing
outward; and a puncture needle which can be freely advanced and
retracted between a first position which is housed inside the
lancet body and a second position which passes through the fluid
channel of the electrochemical sensor mounted on the mounting part
and protrudes from the other one of the surfaces, the
electrochemical sensor including: a base plate provided with a
concave part formed on one of surfaces thereof; a fluid channel
formed so that a bottom part of the concave part and the other one
of the surfaces of the base plate are communicated with each other;
a plurality of electrodes formed on the concave part; a reagent
fixed on the electrodes; a cover which covers the concave part; and
an air channel which causes the inside and outside of the concave
part to be communicated with each other.
10. The lancet according to claim 9, wherein negative pressure for
causing a fluid to flow from the other one of the surfaces to the
one of the surfaces is applied to the fluid channel when a tip part
of the puncture needle is retracted from the second position to the
first position.
11. The lancet according to claim 9, wherein the electrochemical
sensor is mounted on the mounted part in a state of becoming
integral with the lancet body.
12. A bodily fluid measuring apparatus which is able to be equipped
with a lancet, comprising: a plurality of terminals which come in
contact with the respective electrodes of the electrochemical
sensor mounted on the lancet; an electronic circuit which obtains a
measurement signal via the plurality of terminals; and a drive
mechanism which advances and retracts the puncture tool, the
electrochemical sensor including: a base plate provided with a
concave part formed on one of surfaces thereof; a fluid channel
formed so that a bottom part of the concave part and the other one
of the surfaces of the base plate are communicated with each other;
a plurality of electrodes formed on the concave part; a reagent
fixed on the electrodes; a cover which covers the concave part; and
an air channel which causes the inside and outside of the concave
part to be communicated with each other, and the lancet including:
a lancet body; a mounting part which is provided to the lancet body
and to which the electrochemical sensor is mounted in a state of
the one of surfaces facing the lancet body and the other one of
surfaces facing outward; and a puncture needle which can be freely
advanced and retracted between a first position which is housed
inside the lancet body and a second position which passes through
the fluid channel of the electrochemical sensor mounted on the
mounting part and protrudes from the other one of the surfaces.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefits of priority of the
prior Japanese Patent Application No. 2010-115793 filed on May 19,
2010 and the Japanese Patent Application No. 2011-110947 filed on
May 18, 2011, the entire contents of which are incorporated herein
by reference.
FIELD
[0002] The present invention relates to an electrochemical sensor,
a lancet and a bodily fluid measuring apparatus.
BACKGROUND
[0003] In the field of electrochemical sensors, there is a
biosensor which uses enzymes for measuring the glucose
concentration (glucose level) in the blood. For example, there is a
biosensor configured by comprising a base plate in which a working
electrode and a counter electrode are formed on an upper surface, a
spacer which is superimposed on the base plate so as to form a
groove facing a part of the working electrode and the counter
electrode, respectively, a reactive site in which a reaction
reagent layer is formed on a part or all of the groove, and a cover
plate which is superimposed on the spacer, wherein a space that is
surrounded by the groove and the cover plate forms the bodily fluid
passage, and wherein a terminal part which is caused to conduct
respective with the working electrode and the counter electrode and
come in contact with a terminal of the body is disposed at an
appropriate location on an upper surface of the base plate (for
example, Patent document 1).
[0004] The biosensor described in Japanese Patent Application
Laid-open No. 2006-314831 is integrally formed with a tool referred
to as a lancet for opening a small hole (scratching) the skin; for
instance, the fingertip, of a patient. A bodily fluid passage, in
which the reactive site faces the inner surface thereof, is formed
on the inside of the biosensor in the thickness direction thereof
on the one hand, and a through-hole having a diameter that is
larger than the puncture tool which is in communication with the
bodily fluid passage and allows the passage of the tip of the
puncture tool, and which penetrates the sensor in the thickness
direction thereof and is opened to the lower surface of the sensor
is also formed in the biosensor. Consequently, the blood that flows
from the skin that was scratched by the puncture tool is introduced
to the reactive site from the through-hole through the bodily fluid
passage. [0005] [Patent document 1] Japanese Patent Application
Laid-open No. 2006-314831
SUMMARY
[0006] An object of aspects of the invention is to provide an
electrochemical sensor that can be downsized.
[0007] The aspects of present invention adopts the following
configurations in order to achieve the object.
[0008] Specifically, a first aspect of the present invention is an
electrochemical sensor including: a base plate provided with a
concave part formed on one of surfaces thereof, a fluid channel
formed so that a bottom part of the concave part and the other one
of the surfaces of the base plate are communicated with each other,
a plurality of electrodes formed on the concave part, a reagent
fixed on the electrodes, a cover which covers the concave part, and
an air channel which causes the inside and outside of the concave
part to be communicated with each other.
[0009] In the electrochemical sensor of the first aspect, an outer
edge shape in planar view may be a triangle, a trapezoid, or a
circle.
[0010] In the electrochemical sensor of the first aspect, the fluid
channel can be a through-hole formed at the center of the concave
part in planar view, and formed in a direction that is orthogonal
to the base plate.
[0011] Moreover, in the electrochemical sensor of the first aspect,
the air channel may include at least one air hole formed in the
cover.
[0012] Moreover, in the electrochemical sensor of the first aspect,
a planar view shape of the concave part may be formed in a
triangle, and the air channel may include three air holes formed
respectively at positions corresponding to apex portions of the
triangle of the cover.
[0013] Moreover, in the electrochemical sensor of the first aspect,
a planar view shape of the concave part may be formed in a circle,
and the air channel may include an air hole formed on the cover and
disposed so as to overlap with the through-hole in a planar view
state of the base plate.
[0014] Moreover, the electrochemical sensor of the first aspect may
further include a pair of second concave parts formed around the
concave part, and the plurality of electrodes may include a first
electrode pattern in which an electrode extending from the concave
part to one of the pair of the second concave parts and an
electrode removal part are formed integrally, and a second
electrode pattern which is insulated from the first electrode
pattern, and in which an electrode extending from the concave part
to the other one of the second concave parts and an electrode
removal part are formed integrally.
[0015] Moreover, with the electrochemical sensor of the first
aspect, the other one of the surfaces of the base plate may be
recessed inward.
[0016] A second aspect of the present invention is a lancet
including: a lancet body, a mounting part which is provided to the
lancet body and to which the electrochemical sensor according to
the first aspect is mounted, with the one of surfaces facing the
lancet body and the other one of the surfaces facing outward, and a
puncture needle which can be freely advanced and retracted between
a first position which is housed inside the lancet body and a
second position which passes through the fluid channel of the
electrochemical sensor mounted on the mounting part and protrudes
from the other one of the surfaces.
[0017] In the lancet of the second aspect, negative pressure for
causing a fluid to flow from the other one of the surfaces to the
one of the surfaces may be applied to the fluid channel when a tip
part of the puncture needle is retracted from the second position
to the first position.
[0018] In the lancet of the second aspect, the electrochemical
sensor may be mounted on the mounted part in a state of becoming
integral with the lancet body.
[0019] Moreover, a third aspect of the present invention is a
bodily fluid measuring apparatus which is able to be equipped with
the lancet of the second aspect, including a plurality of terminals
which come in contact with the respective electrodes of the
electrochemical sensor of the first aspect mounted on the lancet,
an electronic circuit which obtains a measurement signal via the
plurality of terminals, and a drive mechanism which advances and
retracts the puncture tool.
[0020] According to the present invention, the electrochemical
sensor can be downsized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1A is a plan view schematically showing a configuration
example of the glucose sensor (electrochemical sensor) according to
the first embodiment of the present invention, and FIG. 1B is a
diagram schematically showing a cross section of the glucose sensor
illustrated in FIG. 1A by cutting it at line I-I in FIG. 1A;
[0022] FIG. 2 is an explanatory diagram showing an example of the
manufacturing method of the sensor;
[0023] FIG. 3 is an explanatory diagram showing an example of the
manufacturing method of the sensor;
[0024] FIG. 4 is a diagram showing a modified example of the
sensor;
[0025] FIG. 5 is a diagram showing a modified example of the
sensor;
[0026] FIG. 6 is a diagram showing a modified example of the
sensor;
[0027] FIG. 7 is a diagram showing an example of the bodily fluid
measuring apparatus to which the sensor can be applied;
[0028] FIG. 8A and FIG. 8B are diagrams showing a cross section
configuration example of the mounted body that is mounted on the
body of the bodily fluid measuring apparatus;
[0029] FIG. 9A is a diagram showing the tip surface of the mounted
body that is mounted on the sensor in a planar view, and FIG. 9B is
a diagram showing a state where the sensor is removed;
[0030] FIG. 10 is a diagram showing the electrical configuration of
the sensor and the measuring apparatus;
[0031] FIG. 11A and FIG. 11B are diagrams showing an example of the
lancet with a built-in sensor without the measurement function;
and
[0032] FIG. 12 is a diagram showing a configuration example of the
measuring apparatus without the puncture function.
DESCRIPTION OF EMBODIMENTS
[0033] Embodiments of the present invention are now explained with
reference to the appended drawings. The configurations of the
embodiments are merely examples, and the present invention is not
limited to the configurations of the embodiments.
[0034] <Electrochemical Sensor>
[0035] The electrochemical sensor according to an embodiment of the
present invention is now explained. An electrochemical sensor is a
sensor for detecting a specific test substance by using an
electrochemical reaction, and a biosensor is applied in this
embodiment. A biosensor is used for measuring and detecting a test
substance by using a living substance or a material derived from a
living substance as the element for detecting the test
substance.
[0036] The electrochemical sensor in this embodiment is a biosensor
that is used for measuring the glucose concentration (glucose
level) in the blood, and is referred to as a glucose sensor. The
electrochemical sensor is hereinafter simply referred to as the
"sensor".
[0037] FIG. 1A is a plan view schematically showing a configuration
example of the electrochemical sensor according to the first
embodiment of the present invention, and FIG. 1B is a diagram
schematically showing a cross section of the glucose sensor
illustrated in FIG. 1A by cutting it at line I-I in FIG. 1A.
[0038] In FIG. 1A and FIG. 1B, the sensor 10 as a whole is of a
disk shape having a circular planar shape. The sensor 10 includes a
disk-shaped base plate 11, and a concave part 12 having a flat
circular shape is formed at the center of one surface (upper
surface in FIG. 1B) of the base plate 11. The side wall of the
concave part 12 is formed in a tapered shape where the diameter
becomes smaller toward the bottom surface 12a of the concave part
12, and the surface shape of the concave part 12 is the inner
periphery of a circular truncated cone in which the upper end
thereof is opened. However, it is not an essential requirement for
the side wall of the concave part 12 to be tapered, and the surface
where the concave part 12 is formed can also be formed as a
cylindrical inner surface in which the upper end thereof is
opened.
[0039] A through-hole 13 for causing one surface and the other
surface (lower surface in FIG. 1B) of the base plate 11 to be in
communication is formed at the center of the concave part 12
(center in the diagram). The opening on the other surface side
(lower surface side) of the through-hole 13 is in communication
with a recess 14 formed on the lower surface. The recess 14 is
formed as an inner peripheral shape of a substantial circular
truncated cone in this embodiment. The recess 14 is formed so that
the surface shape of the other surface of the sensor 10 conforms
with the portion where the blood is to be collected (for example,
ball of a finger).
[0040] Note that, in this embodiment, although the through-hole 13
is formed in a direction that is orthogonal to the planar direction
of the base plate, it is not an essential requirement for it to be
formed in an orthogonal direction, and it can also be formed
obliquely. Moreover, the formation of the recess 14 is not an
essential requirement.
[0041] Two second concave parts 15A, 15B are formed around the
concave part 12. The second concave parts 15A, 15B have a circular
planar shape of a diameter that is smaller than the inner diameter
of the concave part 12, and, as with the concave part 12, is formed
as inner periphery of a circular truncated cone having a tapered
shape in which the upper end thereof is opened.
[0042] A metal layer configuring a plurality of electrodes that are
used for measuring the glucose level is formed on the upper surface
of the base plate 11. The plurality of electrodes comprises a
counter electrode 17 that is formed integrally with the electrode
lead line (lead part) from the bottom surface 12a of the concave
part 12 to the second concave part 15A, and a working electrode 16
that is formed integrally with the electrode lead line (lead part)
from the bottom surface 12a of the concave part 12 to the second
concave part 15B (refer to FIG. 3A).
[0043] The working electrode 16 and the counter electrode are
respectively connected to two external terminals which apply a
voltage between the two electrodes and extract a response current.
The external terminals are respectively inserted into the second
concave parts 15A, 15B and respectively come in contact with the
metal layer (working electrode 16, counter electrode 17), and
become an electrically connected state. When, for example, a
connector pin is used as the external terminal, and the respective
connector pins are inserted to fit into the second concave parts
15A, 15B, and the connector pins may come in contact with the
bottom surface of the second concave part 15A (15B) and the metal
layer provided to the lateral surface thereof. Accordingly, since
the contact area may be increased, a favorable contact state may be
obtained in comparison to cases where the metal layer is a flat
surface. Moreover, it is also possible to prevent the connector pin
become shifted in the planar direction of the base plate 11.
However, it is not an essential requirement to provide the second
concave parts 15A, 15B.
[0044] The working electrode 16 is formed to surround the
through-hole 13 and the counter electrode 17 is formed to surround
the working electrode 16 on the bottom surface 12a of the concave
part 12 (refer to FIG. 3A). A gap (groove 24, refer to FIG. 3A and
FIG. 3B) is formed between the working electrode 16 and the counter
electrode 17, and the electrodes are in an insulated state.
[0045] A reagent layer containing enzymes are immobilized on the
electrodes. In the example shown in FIG. 1B, the reagent layer 19
containing enzymes are formed on the working electrode 16.
[0046] As the reactive agent configuring the reagent layer 19, for
example, a type containing glucose oxidase (GOD) as an oxidizing
enzyme and potassium ferricyanide as a mediator is used. When the
reactive site is dissolved by blood, the potassium ferricyanide
coexisting in the reagent layer is reduced due to the commencement
of the well-known enzyme reaction, and potassium ferrocyanide as a
reduction-type electron carrier is accumulated. The amount thereof
is proportional to the substrate concentration; that is, the
glucose concentration in the blood. The reduction-type electron
carrier that has been accumulated for a given period of time is
oxidized due to the electrochemical reaction caused by the
application of voltage between the working electrode 16 and the
counter electrode 17. The current referred to as the anode current
(response current) that is generated here is extracted by the
external terminal and measured by the measuring apparatus, and the
measurement of the glucose level is thereby enabled.
[0047] Note that, as the enzymes for measuring the glucose level,
glucose dehydrogenase (GDH) can be applied in addition to GOD. As
the mediator upon applying GDH, for example, as with the case of
GOD, potassium ferricyanide can be used.
[0048] Moreover, in this embodiment, although a glucose sensor is
illustrated as an example of the electrochemical sensor, it is also
possible to use cholesterol dehydrogenative enzymes (CHDH) as the
enzymes contained in the reagent and use the sensor 10 as the
biosensor (cholesterol sensor) for measuring the cholesterol.
[0049] The upper surface of the base plate 12 is covered by a cover
18 excluding a part of the concave part 12 and the first concave
parts 15A, 15B. As a result of the concave part 12 being covered by
the cover 18, the space surrounded by the concave part 12 and the
cover 18 functions as a capillary, and the through-hole 13
functions as a fluid passage for introducing the bodily fluid
(blood in this embodiment) flowing from the recess 14 side into the
concave part 12 (capillary).
[0050] Accordingly, with the sensor 10 (electrochemical sensor)
according to this embodiment, the fluid channel (through-hole 13)
is formed in thickness direction of the base plate 11 just below
the concave part 12 (capillary). Specifically, the sensor 10
comprises a through-hole 13 which functions as a fluid channel that
causes the bottom surface of the concave part 12 and the other
surface of the base plate 11 to be in communication. In addition,
the blood is sucked from the other surface of the sensor 10 through
the through-hole 13 based on the capillary phenomenon, and
introduced into the concave part 12. Accordingly, the planar
direction size of the base plate 11 can be reduced in comparison a
case of forming the fluid channel in the planar direction of the
base plate 11 as with the conventional technologies. Thus, the
downsizing of the electrochemical sensor can be sought.
[0051] The cover 18 is formed with an opening 18a which functions
as a capillary air hole (air channel) for causing the upper part of
the concave part 12 to be in communication with the outside. In the
example shown in FIG. 1A, the opening 18a is provided at the
approximate center of the concave part 12, and, when the sensor 10
is seen from a planar view, the opening 18a and the through-hole 13
are formed so as to overlap. This overlap is not an essential
requirement. It will suffice so as long as the opening 18a which
functions as the air hole for causing the concave part 12 and the
outside to be in communication is formed above the concave part. As
described later, when a configuration where the puncture needle of
the lancet passes through the through-hole 13 is adopted, the
through-hole 13 and the opening 18a are configured to overlap.
[0052] Moreover, the cover 18 is formed with openings 18b, 18c on
the second concave parts 15A, 15B for inserting the external
terminals into the second concave parts 15A, 15B and causing the
external terminals to come in contact with the electrodes (counter
electrode 17, working electrode 16).
[0053] <Manufacturing Method of Sensor>
[0054] The manufacturing method of the foregoing sensor 10 is now
explained. FIG. 2 and FIG. 3 are explanatory diagrams showing an
example of the manufacturing method of the sensor. Note that,
although FIG. 2 and FIG. 3 illustrate the manufacturing process of
one sensor 10, in reality a plurality of sensors 10 are formed from
one plastic base plate 20. Moreover, in relation to FIG. 2 and FIG.
3, the schematic view of the cross section shown in FIG. 2A and
FIG. 2B and FIG. 3B and FIG. 3C shows the cross section upon
cutting at line X-X illustrated in FIG. 3A.
[0055] A plastic base plate 20 to serve as the base plate 11 is
foremost prepared, and, as shown in FIG. 2A, the concave part 12
and the second concave parts 15A, 15B formed on one surface 21 of
the plastic base plate configuring the base plate 11 (refer to FIG.
3A), and the recess 14 is formed on the other surface 22. In
addition, the through-hole 13 for causing the concave part 12 and
the recess 14 to be in communication in the thickness direction of
the base plate 20 is formed.
[0056] The plastic base plate 20 can be formed from thermoplastic
resin, polyimide resin or epoxy resin such as polyethylene
terephthalate (PET), polypropylene (PP), polyethylene (PE), and
polycarbonate that is harmless to the human body and which as
appropriate insulation properties and elasticity.
[0057] The concave part 12, the second concave parts 15A, 15B, the
recess 14, and the through-hole 13 can be formed via various
plastic molding methods such as the compression method, the
transfer method, or the injection method. When using the plastic
molding method, the concave part 12, the second concave parts 15A,
15B, the recess 14, and the through-hole 13 can be temporarily
formed via the molding process.
[0058] Needless to say, the concave part 12, the second concave
parts 15A, 15B, the recess 14, and the through-hole 13 can be
formed on the base plate 20 via laser irradiation or the machining
process. In the foregoing case, with the example shown in FIG. 2A,
the order of forming the concave part 12, the second concave parts
15A, 15B, the recess 14, and the through-hole 13 can be set
suitably, and they do not need to be collectively formed at
once.
[0059] Next, as shown in FIG. 2B, the metal layer 23 is formed on
one surface of the plastic base plate 20. The metal layer 23 can be
formed, for example, by subjecting metal such as gold or platinum
to physical vapor deposition (PVD; sputtering for instance), or
chemical vapor deposition (CVD).
[0060] Next, a plurality of electrodes are formed on one surface
21. FIG. 3A shows the planar view of the base plate 20 in a state
where the metal layer 23 is formed, and a state where the working
electrode 16 and the counter electrode 17 are formed. As shown in
FIG. 3A, as a result of trimming the metal layer 23 formed on the
one surface 21 by using a laser, the working electrode 16 and the
counter electrode 17 are formed.
[0061] Specifically, the working electrode 16 is formed by
performing laser irradiation so as to form an electrode pattern
(first electrode pattern) of the working electrode 16 containing an
electrode lead line from the concave part 12 to the second concave
part 15B. Moreover, the counter electrode 17 is formed by
performing laser irradiation so as to form an electrode pattern
(second electrode pattern) of the counter electrode 17 containing
an electrode lead line from the concave part 12 to the second
concave part 15A.
[0062] With the portion that was irradiated by the laser, the metal
layer is removed and a groove 24 is thereby formed. Consequently,
the opposing metal layers become an insulated state with the
laser-irradiated portion as the boundary. Thus, in the concave part
12, the working electrode 16 and the counter electrode 17 become an
insulated state across the groove 24 (refer to FIG. 3A and FIG. 3B)
that was formed by removing the metal layer via laser irradiation.
Thus, when laser trimming is applied for forming the electrodes,
the side wall of the concave part 12 is preferably formed in a
tapered shape in which the diameter becomes smaller toward the
bottom surface (for example, the cross section shape of the concave
part 12 is a trapezoid where the base is shorter than the top edge)
so as to form an appropriate groove 24 on the side wall of the
concave part 12.
[0063] Next, the reagent layer 19 is formed (immobilized) on the
working electrode 16. The reagent layer 19 can be formed, for
example, via the divided injection method. Subsequently, the one
surface 21 of the plastic base plate 20 is covered by the cover 18.
The cover 18 can be mounted, for example, by using a sheet-shaped
PET and disposing it on the one surface 21 and performing thermal
fusion bonding thereto. As the cover 18, a cover material in which
openings 18a, 18b, 18c are formed in advance can also be used, or
the openings 18a, 18b, 18c can be formed after the cover material
is mounted (after the thermal fusion bonding).
[0064] Then, as a result of cutting the plastic base plate 20, a
plurality of sensors 10 are cut out from the plastic base plate
20.
Modified Example
[0065] In the example illustrated in FIG. 1A, the planar shape of
the sensor 10 was a circle, but the planar shape can also be
polygonal including a triangle or a rectangle, or oval. Needless to
say, the planar shape of the sensor 10 can also be a triangle as
shown in FIG. 4 or a trapezoid as shown in FIG. 5.
[0066] When the planar shape is formed in a triangle, the number of
sensors 10 that can be obtained from one plastic base plate 20 can
be increased in comparison to the case of forming the planar shape
in another shape. From the perspective of increasing the number of
sensors to be obtained from one plastic base plate 20, the triangle
is preferably an equilateral triangle. Moreover, the same effect
can be yielded when the planar shape of the sensor 10 is formed in
the shape of an isosceles trapezoid where one apex of the triangle
is cut off. The direction of the sensor 10 can be decided easily by
forming the planar shape of the sensor 10 as a trapezoid.
[0067] When the planar shape of the sensor 10 is formed in a
triangle or a trapezoid, as shown in FIG. 4 and FIG. 5, the second
concave parts 15A, 15B are not disposed linearly relative to the
concave part 12 as shown in FIG. 1, but are rather disposed, for
example, on the straight line that connects the center of the
triangle or the trapezoid, and the respective apexes which are
formed by the base of the triangle or the trapezoid and the other
sides. In the foregoing case, the cross section upon cutting the
sensor at line II-II of FIG. 4 and the cross section upon cutting
the sensor 10 at line III-III of FIG. 5 will be the same as the
structure shown in FIG. 1B. Needless to say, the position of the
second concave parts 15A, 15B relative to the concave part 12 can
be suitably set. Moreover, the planar shape of the second concave
parts 15A, 15B can also be suitably set.
[0068] Moreover, although the planar shape of the concave part 12
was a circle in the example shown in FIG. 1A, preferably, the
concave part 12 is formed in a triangle with the sensor 10 in which
the planar shape is a triangle as shown in FIG. 4, and formed in a
trapezoid with the sensor 10 in which the planar shape is a
trapezoid as shown in FIG. 5. As described above, when the planar
shape of the concave part 12 is formed in the same shape
(particularly a similar figure) as the planar shape of the sensor
10, this is preferable from the perspective that the capacity of
the capillary that is formed by the concave part 12 can be
maximized.
[0069] Moreover, when the planar shape of the concave part 12 is a
triangle, preferably, while the through-hole 13 is positioned at
the center of the triangle, the three openings 18a are disposed so
as to overlap with the respective apexes of the triangle of the
concave part 12. Consequently, these will be disposed at positions
where the distance between the inlet (upper end of the through-hole
13) of the blood provided at the center of the concave part 12 and
the respective air holes (respective openings 18a) becomes the
greatest, and the blood that flows from the center of the concave
part 12 through the through-hole 13 will spread evenly in the
concave part 12. Thus, the time required for the blood to reach the
air hole (opening 18a) and air bubbles to be eliminated can be
prolonged.
[0070] Moreover, in the example of the sensor 10 according to this
embodiment described above, a case where the reagent layer 19 is
formed on the working electrode 16 was explained. However, the
reagent can also be disposed across the working electrode 16 and
the counter electrode 17. The reagent layer 19 preferably covers
the overall upper surface of the working electrode 16, but when it
is placed across the counter electrode 17, it will suffice if a
part of the counter electrode 17 is covered.
[0071] <Bodily Fluid Measuring Apparatus and Lancet>
[0072] The bodily fluid measuring apparatus to which the foregoing
sensor 10 is applied and the lancet are now explained. FIG. 7 is an
overall external view of the bodily fluid measuring apparatus
according to this embodiment, and FIG. 8A is an enlarged
longitudinal cross section showing the details of the mounted body
in a state where the puncture tool is retracted and is a diagram
corresponding to the cross section along line IV-IV of FIG. 4. FIG.
8B is an enlarged longitudinal cross section showing the details of
the mounted body in a state where the puncture tool is advanced.
FIG. 9A is a bottom surface view of the mounted body, and FIG. 9B
is a bottom surface view of the mounted body in a state where the
sensor is removed.
[0073] As shown in FIG. 7 to FIG. 9, the bodily fluid measuring
apparatus 30 is used by combining the body 40 and the mounted body
50 (corresponds to the lancet body). The body 40 has switch buttons
(not shown) and an LCD display device 32 disposed on its upper
surface. A tubular part 41 is formed in a protruding manner at the
front part of the body 40, and a cap-shaped mounted body 50
described later is mounted on the tip part of the tubular part
41.
[0074] A drive mechanism (71, 72) for forward-driving the puncture
tool 61 of the mounted body 50 and an electronic circuit of a
microcomputer or the like are built into the body 40. The drive
mechanism is provided at the rear of the body 30 in FIG. 1, and
includes a pressing part 71 to be manually pressed by the user.
[0075] A configuration example of the mounted body 50 is now
explained with reference to FIG. 8A, FIG. 8B, FIG. 9A and FIG. 9B.
The mounted body 50 is formed in a substantial cap shape comprising
a cylindrical part 54, and a bottom wall part 55 positioned so as
to cover the tip of the cylindrical part 54 in the cylindrical part
54. The main parts of the cylindrical part 54 and the bottom wall
part 55 can be prepared by resin molding.
[0076] The end part 41a of the tubular part 41 of the body 40 is
formed to have a diameter that is smaller than the base end part of
the tubular part 41, and the inner diameter of the cylindrical part
54 corresponds to the outer diameter of the end part 41a of the
tubular part 41, and the mounted body 50 is fitted and fixed to the
end part 41a by covering the end part 41a. Accordingly, the mounted
body 50 can be easily mounted removably to a predetermined location
of the body 40 (end part 41a of the tubular part 41). The outer
surface of the bottom wall part 55 functions as the mounting
surface for mounting the sensor 10 described above (refer to FIG.
1).
[0077] A puncture tool 61 is mounted on the bottom wall part 55 of
the mounted body 50. In addition, the side face of the sensor 10 is
fitted into the inner circumferential wall 54a of the cylindrical
part 54, the upper surface of the sensor 10 comes in contact with
the lower surface of the bottom wall part 55, and the sensor 10 is
thereby mounted on the mounted body 50. A cylindrical housing part
55A having a discoid wall 55a, a cylindrical wall 55b, and a bottom
wall 55c with an opening 155a (refer to FIG. 9B) at the center is
formed at the center position of the mounted body 50 at the bottom
wall part 55, and a center hole 55d is opened at the bottom wall
55c of the housing part 55A.
[0078] The puncture tool 61 is configured by a metal puncture
needle 61c being mounted coaxially and integrally on a resin guide
body 61A having a guide shaft 61a which slidably fits with the
center hole 55d, and a flange part 61b which is formed integrally
with one end of the guide shaft 61a.
[0079] In the housing part 55A, an elastic body 67 is interposed
between the lower surface of the flange part 61b and the upper
surface of the cylindrical wall 55a. In the case shown in FIG. 8A
and FIG. 8B, the elastic body 67 is a coil spring that presses
(biases) the flange part 61b in a direction of being separated from
the discoid wall 55a. Needless to say, in substitute for the coil
spring, urethane foam can also be used. Otherwise, the elastic body
37 can also be a plate-shaped spring that is integrally formed with
a resin guide body 61A.
[0080] Based on the elastic body 67, the flange part 61b is biased
toward the retract position (first position) shown in FIG. 8A; that
is, toward the position in which the flange part 61b comes in
contact with the bottom wall 55c. In the retract position, the rear
end (upper end) of the guide shaft 61a will protrude from the
housing part 55A, and the tip part of the puncture needle 61c will
retract inside the housing part 55A.
[0081] As described above, the sensor 10 is mounted on the mounted
body 50 so as to cover the housing part 55A housing the puncture
tool 61. A case where the sensor 10 is fitted inside the
cylindrical part 54 was explained above, but the sensor 10 can also
be attached to the bottom wall part 55.
[0082] The sensor 10 is mounted in a state where one surface (upper
surface) faces the bottom wall part 55 and the planar direction of
the sensor 10 is orthogonal to the center axis of the cylindrical
part 54. In this mounted state, the opening 18a (air hole) of the
sensor 10 and the through-hole 13 (fluid channel) are disposes
substantially coaxial with the puncture needle 61c in the axis
direction of the cylindrical part 54 (FIG. 9A).
[0083] As shown in FIG. 8A and FIG. 8B, as well as FIG. 9A and FIG.
9B, round holes 162a, 162b are formed on the bottom wall part 55 of
the mounted body 50 at positions corresponding to the second
concave parts 15A, 15B of the sensor 10. The round hole 162b is
used for causing one tip of the connector pins 35a provided inside
the body 20 to come in contact with the electrode lead line of the
metal layer; that is, the working electrode 16, formed on the
second concave part 15B when the mounted body 50 is mounted on the
body 30 (tubular body 40). Meanwhile, the round hole 162a is used
for causing the other tip of the connector pins 35a provided inside
the body 20 to come in contact with the electrode lead line of the
metal layer; that is, the counter electrode 17, formed on the
second concave part 15A when the mounted body 50 is mounted on the
body 30 (tubular body 40).
[0084] Meanwhile, a pair of pin connectors 35 is disposed in
parallel in the tubular part 41 of the body 30 in its axis
direction, and configured such that the connector pins 35a
elastically protrude from the tip part of the pin connectors 35.
One connector pin 35a passes through the round hole 162a and the
opening 18c of the sensor 10 and is inserted into the second
concave part 15B, and comes in contact with the electrode lead line
of the working electrode 16. The other connector pin 35a passes
through the round hole 162b and the opening 18b of the sensor 10
and is inserted into the second concave part 15A, and comes in
contact with the electrode lead line of the counter electrode
17.
[0085] The pin connectors 35 are connected to the electronic
circuit 33 as shown in FIG. 10. The electronic circuit 33 is
configured from a microcomputer, a memory and the like, and, by the
microcomputer executing a program stored in the memory, it
functions to determine the measured value of the specimen such as
its glucose level by using the standard curve from the enzyme
reaction and electrochemical reaction that occur in the capillary
of the sensor 10 as described later, and display the measured value
on a display device 32 disposed on the surface of the body 40.
[0086] Moreover, a pressing rod 72 for causing the inside of the
tubular part 41 of the body 40 to retreat in the axis direction of
the tubular part 41 according to the pressing operation of the
pressing part 71 shown in FIG. 7 is disposed in the body 40. The
pressing rod 72 is biased toward the pressing part 71 side
(rearward side) by a spring not shown. The drive mechanism
including the pressing part 71 and the pressing rod 72 is
configured as described above. Consequently, when the pressing part
71 is pressed, the pressing rod 72 moves toward the front side (tip
side) against the biasing force of the spring, comes in contact
with the rear end part of the guide shaft 61a, and thereby presses
the puncture tool 61A forward.
[0087] The tip part of the puncture needle 61c of the puncture tool
61A thereby passes through the opening 18a of the sensor 10 and the
through-hole 13 and moves to the second position which protrudes
outward from the lower surface of the sensor 10. Thus, the outer
diameter of the puncture needle 61c is formed to be a smaller
diameter than the inner diameter of the through-hole 13.
[0088] The inside of the housing part 55A is of a state where the
side face of the flange part 61b and the inner peripheral surface
of the cylindrical wall 55b are in contact, and, when the flange
part 61b advances forward (downward) from the retract position, the
air in the housing part 55A will be discharged to the outside
through the through-hole 13 if the through-hole 13 is not covered.
Meanwhile, even if the lower end of the through-hole 13 is covered
by skin or the like, the flange part 61b as a result of the air
inside the housing part 55A being compressed. In the foregoing
case, when the pressing rod 72 retreats and the flange part 61b is
pressed backward (upward) by the biasing force of the elastic body
67, negative pressure is generated inside the housing part 55A.
This negative pressure induces the effect of causing the fluid
existing in the recess 14 of the sensor 10 to be drawn into the
concave part 12 (capillary) via the through-hole 13. Accordingly,
when the puncture needle 61c is retreated, the fluid (blood)
existing in the recess 14 will be introduced into the concave part
12 through the through-hole 13 (fluid channel) based on the
negative pressure that was generated in the housing part 55A, in
addition to the capillary action.
[0089] Note that, as the drive mechanism, without limitation to the
illustrated example, it is also possible to adopt a configuration
of providing a pressing rod 72 capable of moving in the axis
direction and which will elastically return to the neutral position
in the axis direction, bending the pressing rod 72 backward to
retain the latch, pressing the latch release button so that the
pressing rod 72 advance forward forcefully, the pressing rod 72
forcefully hammering the rear end of the guide shaft 61a of the
puncture tool 61, and thereby causing the puncture needle 61c to
instantaneously protrude from the other surface (lower surface) of
the sensor 10.
[0090] Moreover, as the terminal (external terminal) that is
provided inside the body 40 so as to enable conductive conduct with
the terminal parts of the sensor 10 (respective electrode lead
lines of the working electrode 16 and the counter electrode 17)
when the mounted body 50 is mounted on the body 40, in addition to
applying the pin connector 35 in which the pin is constantly
protruding elastically as described above, for example, it is also
possible to adopt a configuration where, in coordination with the
mounting of the mounted body 50 on the body 40, the terminal pin is
retreated inside the body when the mounted body 50 is not mounted,
and appropriate conductive conduct is sought with the terminal part
of the biosensor as a result of the terminal pin protruding from
the body when the mounted body 50 is mounted.
[0091] The method of use and operation of the bodily fluid
measuring apparatus 30 comprising the foregoing configuration are
now explained with reference to FIG. 7 to FIG. 10.
[0092] The mounted body 50; that is, the lancet with the built-in
sensor is provided as a disposable consumable supply, and, upon
using the bodily fluid measuring apparatus 30, the user mounts the
mounted body 50 on the tubular part 41 of the body 40 (refer to
FIG. 7).
[0093] Since the mounted body 50 is formed in a cap shape, the
foregoing mounting process can be performed easily. When the
mounted body 50 is mounted, as shown in FIG. 8A, the tip of the
connector pins 35a housed in the body 40 automatically comes in
contact with the second concave parts 15A, 15B via the round holes
162a, 162b of the bottom wall part 55 of the mounted body 50 and
the openings 18b, 18c of the sensor 10. Consequently, the counter
electrode and the working electrode 16 become electrically
connected with the measuring apparatus 30.
[0094] The tip of the mounted body 50; that is, the lower surface
of the sensor 10 is pressed against an appropriate location of the
skin of the user or the patient; for example, the fingertip or
earlobe. Here, since the recess 14 is formed on the lower surface
of the sensor 10, the lower surface of the sensor 10 can be caused
to come in contact with the skin in a favorable state.
[0095] In the foregoing state, when the pressing part 71 (FIG. 7)
is pressed downward, based on the stroke where the tip of the
pressing rod 72 housed inside the body 40 presses the rear end part
of the guide shaft 61a of the puncture tool 61, and the tip of the
pressing rod 72 comes in contact with the housing part 55A, the
puncture tool 61 at the retract position (first position) is
pressed forward against the elastic force (biasing force) of the
elastic body 67.
[0096] Here, the puncture needle 61c of the puncture tool 61 passes
through the opening 18a, the concave part 12, and the through-hole
13 of the sensor 10 and protrudes from the lower surface of the
sensor 10 a predetermined length (advances to the second position
(advance position); refer to FIG. 8B). When the pressing to the
pressing part 71 is released, the pressing rod 72 returns to its
original position based on the elastic force of a spring not shown.
Moreover, the puncture tool 61 also returns to the retract position
(first position) where the tip of the puncture needle 61c enters
the housing part 55A based on the elastic force of the elastic body
67 (refer to FIG. 8A).
[0097] Due to the protrusion of the puncture needle 61c, the skin
is scratched appropriate, and the blood flowing from the scratch is
introduced into the concave part 12; that is, the capillary, via
the through-hole 13 due to the negative pressure that is generated
within the housing part 55A based on the capillary phenomenon and
the retreat of the puncture tool 61. Specifically, since the blood
will be introduced into the capillary, which is the target
position, if it flows a distance of the length of, or a distance
that is slightly longer than, the through-hole 13, the capillary
can be filled with blood with a small amount of blood and in a
short period of time.
[0098] Accordingly, the user can introduce sufficient blood, which
is required for measurement, into the capillary (concave part 12)
of the sensor 10 by performing the pressing operation in a state of
pressing the sensor 10 against the skin without having to visually
confirm the amount of blood of the bleeding part, and then
maintaining the state after releasing the pressing force.
[0099] In the concave part 12, when the reagent layer 19 is
dissolved by the blood, the potassium ferricyanide that coexists in
the reagent layer 19 is reduced due to the commencement of the
enzyme reaction of the enzymes (GOD) contained in the reagent layer
19, and potassium ferrocyanide as a reduction-type electron carrier
is accumulated.
[0100] The cumulative dosage of the potassium ferrocyanide is
proportional to the substrate concentration; that is, the glucose
concentration in the blood. The reduction-type electron carrier
that has been accumulated for a given period of time is oxidized
due to the electrochemical reaction caused by the application of
voltage between the working electrode 16 and the counter electrode
17.
[0101] The electronic circuit 43 in the body 40 of the measuring
apparatus 30 computes and determines the glucose concentration
(glucose level) from the working current (response current) that is
measured via the pin connectors 35, and displays the results on the
display device 32.
[0102] Thus, according to the bodily fluid measuring apparatus 30,
measurement of a bodily fluid such as the glucose level can be
appropriately performed only based on an operation of causing the
puncture needle 61c to protrude as though handling a conventional
lancet while retaining the sensor 10 mounted on the front surface
of the mounted body 50 in a state of being pressed against the
fingertip or earlobe of the patient, after a simple preliminary
preparation of mounting the mounted body 50 on a predetermined
location of the body 40, without requiring any additional operation
or movement. Moreover, after use, the mounted body 50 can be
disposed without touching the blood merely by holding the side
surfaces of the mounted body 50 and removing it from the body 40
and disposing the same.
[0103] Note that, in the example shown in FIG. 7 to FIG. 10, a case
where the sensor 10 is formed integrally with the mounted body 50
as the lancet was explained. Needless to say, the sensor 10 shown
in this embodiment can also be used independently; that is, by
pinching the sensor 10 with fingers or the like and pressing the
lower surface of the sensor 10 to the blood flowing from the skin
using a lancet or the like, the capillary can be filled with the
blood, and the sensor 10 can be subsequently set on the measuring
apparatus in order to measure the blood.
[0104] Moreover, as shown in FIG. 11A and FIG. 11B, the sensor 10
can also be applied to the lancet 140 to which the foregoing
mounted body 50 is mounted. In the example shown in FIG. 11A and
FIG. 11B, the lancet 140 is not provided with components (pin
connector 35) for enabling the electrical connection with the
sensor 10, and the pressing part 173 that is formed integrally with
the pressing rod 72 is caused to protrude rearward of the body 141
by the tension springs 142 provided inside the body 141. With this
kind of lancet 140, by pressing the pressing part 173, it is
possible to cause the puncture needle 61c to protrude from the
lower surface of the sensor 10, and fill the concave part 12 with
blood.
[0105] Subsequently, the mounted body 50 is dismounted from the
body 141, and the mounted body 50 is mounted on the end part 41a of
the tubular part 41 of the body 40 as shown in FIG. 12. The
pressing rod 72 is not provided inside the body 41 shown in FIG.
12. Moreover, although not shown, the pressing part 71 is omitted
from the external view of the measuring apparatus 30 shown in FIG.
7. Meanwhile, the pin connectors 35 are housed inside the body
shown in FIG. 12, and, as with the similar effect described above,
the connector pins 35a automatically come in contact with the
working electrode 16 and the counter electrode 17, and the sensor
10 and the measuring apparatus 30 become electrically
connected.
[0106] Otherwise, in substitute for the configuration of the lancet
140 shown in FIG. 11; that is, in substitute for the body 141 and
the mounted body 50 being formed integrally, the sensor 10 can be
removably attached to the lancet, and the sensor 10 in which the
capillary (concave part 12) is filled with blood can be set in the
measuring apparatus (not shown). Here, a chuck mechanism can be
provided to the tip part lancet so that the sensor 10 is retained
by the chuck mechanism.
[0107] Note that, in the configuration example of the lancet
(mounted body 50, lancet 140) of the embodiment described above, a
case where the sensor 10 in which air holes (openings 18a) are
formed in advance is mounted on the lancet was explained. Needless
to say, with the configuration of the lance of this embodiment,
since the puncture needle 61c passes through the cover 18 of the
sensor 10 since the puncture needle 61c passes through the
through-hole 13, the air holes can be consequently formed on the
cover 18. Thus, it is also possible not to form the air holes in
advance.
[0108] Moreover, it is also possible to adopt a configuration where
a separate needle, which coordinates with the puncture needle and
has a diameter that is larger than the puncture needle, is provided
inside the lancet, the separate needle also advance according to
the advancement of the puncture needle, and the air holes are
formed at the appropriate positions on the cover.
[0109] Needless to say, from the perspective of reliability of the
air holes that are formed by the puncture needle 61c and the
separate needle, it is preferable to form in advance the openings
18a (air holes) having an inner diameter that is larger than the
outer diameter of the puncture needle 61c.
[0110] Moreover, in the example shown in FIG. 7 to FIG. 12, the
sensor 10 in which its planar shape is a circle was illustrated,
but the bodily fluid measuring apparatus 30 (mounted body 50, body
40) and the lancet 140 of this embodiment can be applied
irrespective of the planar shape of the sensor 10. For example, the
sensor 10 as shown in FIGS. 4 to 6 can be applied. However, the
shape of the mounting part of the sensor 10 in the mounted body 50
is modified so that it can retain the sensor 10 (for instance, so
that the sensor 10 can be fitted therein) according to the planar
shape of the sensor 10. Moreover, the position of the pin
connectors 35 and the round holes 162a, 162b is changed according
to the position of the second concave parts 15A, 15B.
* * * * *